I skimmed over that paper, and may do a deeper dive later, although doesn't really seem worth it. I thought it was going to be a scientific study, but it reads more like a essay from two authors with a specific viewpoint trying to convince others, via slanted/biased text, that other text and language is baising an entire industry and population? I find that questionable at best.

And while the authors made a lot of claims, and cited some other studies, they don't really, IMO, prove their point in any scientifically valid way, or even as a solid, well-formed argument. Add in that the authors are sociologists, not neuroscientists or psychiatrists/psychologists, and it makes me question both their claims and understanding of the topic.

I did catch that one of their main points (that you mentioned as well) boils down to not having a physical test or clear biomarker. But that applies to nearly all psychiatric conditions. Saying the absence of those kinds of tests is the same as the absence of a real condition ignores the research that has been done demonstrating functional impairment (including twin studies, some indications of genetic heritability). The paper presents a specific sociological viewpoint, and that isn't the current scientific consensus.

Like I said, probably not gonna convince you, just dropping this for others that might see the essay link and think it might actually provide validity when it does not. That essay does not really make significant arguments against ADHD.

It does present good warnings to be aware of pressures that would distort diagnosis and I do think there is good reason to be cautious about over diagnosing, or diagnosing by unqualified personnel, both of which do happen of course. But the article goes too far beyond that.